Floating dock or the like and floatation unit for use therewith

ABSTRACT

A floating dock, raft or the like is made with special plastic floatation units. The floatation units consist of a pair of vacuum formed polyethylene sheets heat sealed together at peripheral flanges thereof. This flange is nailed to the bottom of joists which support the deck material of the dock.

United States Patent Shuman 1 Aug. 14, 1973 FLOATING DOCK OR THE LIKEAND 09. 8 11/1963 FLOATATION UNIT FOR USE THEREWITH 3,131,417 5/1964 I3,171,141 3/1965 [75] inventor: Robert A. Shuman, Plymouth, Mich.3,193,855 7/1965 [73] Assignee: Woodall Industries Inc., East Detroit,Mich Primary Examiner-Milton Buchler Assistant Examiner-Jesus D. Sotelo22 F1 d: S t. 22 1971 l 1 1e ep Attorney-Hamess, Dickey & Pierce [21]App1.No.: 182,744

52 us. 0..., 114/.5 F 1 ABSTRACT giitidCLig..1..1.;./..5...RB6gbF351/2030 A floating dock raft of the like is madewith special 7 :9 7 R 8 5/ plastic floatation units. The floatationunits consist of i 65 a pair of vacuum formed polyethylene sheets heatsealed together at peripheral flanges thereof. This flange is nailed tothe bottom of joists which support [56] References Cited the deckmaterial of the dock. UNITED STATES PATENTS n I 2,879,735 3/1959 Pointer9/11 R 14 Claims, 5 Drawing Figures 1 FLOATING DOCK OR THE LIKE ANDFLOATATION UNIT FOR USE THEREWITII SUMMARY OF THE INVENTION It has beencommon practice in the construction of rafts, floating docks and otherwater buoyant devices to employ barrels or drums as floatation units.Four or more steel barrels, when they are empty, will serve to support aconsiderable weight of framing and deck material well above the waterline. While the use of steel barrels in such construction has been auseful expedient, this practice has a number of serious drawbacks. Docksand the like made with steel barrels are extremely heavy and are quitedifficult to put in and take out of the water. The steel of the barrelstends to rust and specially designed brackets are often needed to securethe barrels to the framework of the dock or raft. Furthermore, the typeof framework required with barrels must necessarily be of a sizable andexpensive nature. Also, the decking is often supported at a greaterheight above the water than is desirable. The present invention relatesto a floating dock, raft or similar device and a special floatation unitwhich is used therein in lieu of steel barrels. The arrangement of thepresent invention has a number of marked advantages over prior floatingdocks and raft constructions.

The device of the present invention is relatively easily constructed byan individual having few or no special skills. Apart from the specialfloatation units, a dock, raft or the like can be constructed withconventional, readily available, low cost materials. The amount ofmaterial needed for the framework is particularly minimal and low incost. The resulting product is relatively light in weight, low in costand requires minimal maintenance. Furthermore, it is of a durable andrelatively rugged character.

The floatation units themselves can be manufactured and sold at areasonable cost, they possess a high structural strength for theirweight, and they are uniquely suited for use in the construction offloating docks, rafts, diving platforms and other floating devicesoperable to support humans or materials on water. The floatation unitsare substantially maintenance free, yet they are easily repaired ifdamaged.

The foregoing advantages of the present invention will be readilyapparent from the ensuing description of the preferred embodiments ofthe invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of afloatation unit constructed in accordance with the present invention;

FIG. 2 is an end elevational view on a reduced scale of the structureillustrated in FIG. 1;

FIG. 3 is a top plan view of a floating dock made with the floatationunit of FIGS. 1 and 2, most of the decking of the dock being broken awayto illustrate the subjacent structure;

FIG. 4 is an enlarged sectional view of the structure illustrated inFIG. 3, taken along the line 44 thereof; and

FIG. 5 is a top plan view of a raft made in accordance with the presentinvention, the major portion of the decking of the raft being removed toillustrate the subjacent structure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION The floatingdock of FIGS. 3 and 4 employs four floatation units of the type shown inFIGS. I and 2. The floatation unit per se is designated by the numeral10 and is best seen by reference to FIGS. I, 2 and 4. The unit 10 ismade from an upper plastic sheet 12 and a lower plastic sheet 14. Thesheets 12 and 14 are desirably of polyethylene material and are vacuumformed by means of the method and apparatus shown in U. 5. Pat. Nos.3,242,245 and 3,250,660. The upper sheet 12 has a central upwardlydished portion 16 which is surrounded at its lower end by a planarperipheral flange 18. The lower sheet 14 has a downwardly dished centralportion 20 which is surrounded at its upper end by a planar peripheralflange 22. The formed or upwardly dished portion 16 of the top sheet 12will be seen to include a generally flat horizontal top wall 26 which isconnected to the flange 18 by downwardly and outwardly inclined sidewalls 28 and end walls 29. The downwardly dished portion 20 of the lowersheet 14 will be seen to include a semi-cylindrical wall 30 which blendswith straight side walls 32 at its upper ends. The straight side walls32 connect the semi-cylindrical wall 30 with the flange 22. Generallyflat end walls 33 enclose the lower dished portion 20 at the oppositeends thereof and merge with the flange 22.

Both the top and bottom sheets 12 and 14 are provided with suitablestrengthening ribbing which contributes to the strength and rigidity ofthe floatation unit 10. Inwardly deformed ribs 34 are formed in theupper sheet end walls 29 and extend upwardly from the flange 18 to thetop wall 26. Inwardly deformed transverse ribs 36 are formed in the topwall 26 and side walls 28 and extend from one side of the floatationunit to the other side thereof. The lower sheet 14 is similarly providedwith inwardly deformed ribs 38 in the end walls 33 thereof and withinwardly deformed transverse ribs 40 in the wall 30 and walls 32thereof. The ribs 40 extend from the portion of the flange 20 at oneside of the unit to the portion of the flange 20 on the opposite sidethereof. Load supporting vertical ribs 42 are formed on all sides of thelower sheet dished portion 20 in columnar supporting relation to theflange 22. It will be seen that the ribs 42 extend downwardly from theflange 22 and outwardly from the walls 32 and 33. The ribs 42, ofcourse, constitute outward deformations of the walls 32 and 33. Aplugged hole 44 is formed in the floatation unit 10 between the flangesl8 and 22 to facilitate the emptying of water from the unit in the eventof a leak.

The two sheets 12 and 14 are heat sealed together at their flanges I8and 22. The flanges l8 and 22 thus become one solid flange for thefloatation unit which will hereafter be referred to as the flange 18-22.This flange will be seen to be uninterrupted on its upper surface andsupported on its lower surface by the ribs 42. The formed or dishedportions 16 and 20 of the sheets 12 and 14 define a substantially watertight compartment 45 which normally contains only air at atmosphericpressure and provides the unit 10 with the desired buoyancy.

The floatation unit 10 may be utilized to construct various floatingstructures such as floating docks, rafts, diving platforms or the like.Such structures may differ in size or shape although they have certaincommon structural features. One such structure in the form of a floatingdock is illustrated in FIG. 3. This dock will be seen to have aframework which includes a plurality of parallel long joists 46 andparallel short joists 48 set at right angles to the long joists 46.Joists in the form of angular struts 50 connect the joists 46 and 48 atthe outer ends thereof. The joists 46 and 48 as well as the struts 50desirably consists of lumber such as standard 2 X6 inch lumber. Rightangle steel brackets 52 are used at the junctures ofjoists 46 and 48while brackets 56 are used at the joints between struts 50 and thejoists 46 or 48. The joists 46 and 48 are set on edge on the uppersurfaces of the flanges 18-22 of four floatation units 10 while a deckin the form of plywood panels 58 is fastened to the joists 46 and 48 bynails 60. As seen in FIG. 4, the plywood deck panels 58 rest on theupper edges 62 of the joists 46 while lower edges 64 of the joists 46rest on the upper surface of the flanges 18-22. The nails 60 are alsoused to secure the joists 46 and 48 to the flanges 18-22 of thefloatation units 10, the nailing being accomplished from the undersideof the flanges. The joists 46 and 48 are thus positioned in verticalattitudes and extend horizontally with their upper surfaces in a commonplane and their lower surfaces in a common plane. In the particular dockillustrated in FIG. 3, a pair of floatation units 18 are positionedbetween thejoists 46 at the opposite ends thereof. A third floatationunit 10 is positioned between one pair of short joists 48 at their outerends and a fourth floatation unit is positioned between another pair ofshort joists 48 at their outer ends. The resulting structure, as seen inplan view, is a polygon having four long sides and four short sides withfloatation units being positioned at each of the four short sides. Thisarrangement gives good balance and stability to the dock and ismanufactured at a relatively low cost.

The floatation unit 10 has been designed so that lumber of aconventional, inexpensive size may be employed for the joists 46 and 48.The flat top wall 26 of the unit 10 is spaced above the flange 18-22less than the vertical height of the joists 46 and 48 and will lieclosely beneath the deck 58. it will be seen that the flange 18-22 ismuch closer to the flat top wall 26 than it is to the bottom of thefloatation unit. This permits the use of joists of short vertical heightin the construction of the dock framework. While the members 46 and 48have been characterized as joists, it will be apparent that variousbraces, supports, beams, stringers or frame members could be used as aconnection between the deck 58 and the flanges 18-22. As used herein,the word joist" is intended to refer generically to all such horizontalelongated members. It should also be noted that only portions of theflange 18-22 on opposite sides of the floatation unit 10 need beutilized to support the joists. Accordingly, it would be possible tointerrupt or remove portions of the flange 18-22 which are not neededfor such purpose. It will be apparent, however, that the ribs 42 performa highly desirable function in resisting downward deflection of theflange 18-22 and contribute to the overall load supporting capability ofthe unit 10.

Should the unit 10 become punctured, it is relatively easily repaired.If made from polyethylene, it is only necessary to melt additionalpolyethylene onto the puncture hole in order to reclose the same. Anywater which has leaked into the float can be emptied through theclosable or plugged hole 44. The various ribs 34,

36, 38 and 40 add substantially to the stiffness of the sheets 12 and 14without interferring with the assembly of the floatation unit 10 to theframework of joists 46 and 48 and without materially detracting from thebuoyance of the unit.

Another form of the invention is illustrated in FIG. 5 and consists of araft having four parallel joists 68. The joists 68 are joined at theiropposite ends to cross members 70 while a deck 72 is nailed to the upperedges of the joists. A pair of floatation units 10 are positionedbetween one pair of joists 68 at the opposite ends thereof while asecond pair of floatation units 10 are positioned between a second pairof joists 68 at the opposite ends thereof. The joists 68 rest on theupper surfaces of the floatation unit flanges 18-22 and are nailedthereto from the underside of said flanges. A motor mounting board 74for supporting a motor 76 may, if desired, be nailed to one of the crossmembers 70. It will be apparent that a purchaser of four floatationunits 10 can construct the raft of FIG. 5 with a minimal amount oflumber, plywood and nails. The joists 68 are stabilized at their upperedges by the deck 72 and at their lower edges by the floatation units10, in addition to the stabilization given thereto by the cross members70, which are end nailed to the joists 68. Accordingly, the entirestructure is quite rigid as well as being very light.

What is claimed is:

l. A floating load supporting structure comprising a framework having aplurality of parallel joists, a deck mounted on said joists and aplurality of floatation units positioned between and supporting saidjoists, said floatation units being made from upper and lower thinwalled plastic members joined at peripheral flange portions thereof todefine a water tight compartment between said members, said flangeportions being disposed in a horizontal plane located intermediate theupper and lower extremities of said floatation units, and fastener meansextending upwardly through said flange portions into said joists tosecure said flange portions to said joists.

2. The structure set forth in claim 1 in which one thin walled member ofsaid floatation unit is upwardly dished from said flange and in whichthe other thin walled member of said floatation unit is downwardlydished from said flange.

3. The structure set forth in claim 1 in which said floatation unitflange portions are heat sealed together.

4. The structure set forth in claim 1 in which said joists compriselumber of greater height than width.

5. The structure set forth in claim 1 in which one of said floatationunit members incorporates an upwardly formed central portion having asubstantially flat upper wall and in which the other floatation unitmembers incorporates a central downwardly formed portion having anarcuate wall.

6. The structure set forth in claim 1 in which a lower one of themembers of said floatation units incorporates outwardly projecting ribssupportingly connected to said flange portions on the lower sidethereof.

7. A floatation unit for floating docks, rafts or the like comprising apair of formed synthetic resinous top and bottom sheets, said sheetshaving peripheral flanges sealed together to define a water tightcompartment in the space between said sheets, said top sheet beingupwardly formed in the area thereof bounded by its said flange and beingunobstructed in areas above its said flange on opposite sides thereof topermit a pair of joists or the like to be supported thereon, said bottomsheet having load supporting ribs formed therein and connected to itssaid flange to reinforce said flanges against downward deflection.

8. The structure set forth in claim 7 in which said top sheet has acentral upwardly deformed portion located entirely above the plane ofsaid flange portions and in which said bottom sheet has a downwardlydeformed portion located entirely beneath the plane of said flangeportions.

9. The structure set forth in claim 8 in which said top sheet isprovided with a raised generally flat top wall at the upper end thereofand in which said bottom sheet is formed with a depressed arcuate wallat the lower end thereof.

10. The structure set forth in claim 7 in which the flange portions ofsaid sheets are heat sealed together.

11. The structure set forth in claim 7 in which one of said sheets isformed with inwardly depressed reinforcing ribs.

12. The structure set forth in claim 7 in which said flange portions arelocated in a plane disposed above a point midway between the top of saidtop sheet and the bottom of said bottom sheet.

13. The structure set forth in claim 7 in which each of said sheets isprovided with a peripheral flange extending entirely therearound and inwhich said flanges are heat sealed together.

14. The structure set forth in claim 13 including load supporting ribsdeformed outwardly from said lower sheet and merging with the flange ofsaid lower sheet to provide columnar support against downward deflectionof said lower sheet flange.

1. A floating load supporting structure comprising a framework having aplurality of parallel joists, a deck mounted on said joists and aplurality of floatation units positioned between and supporting saidjoists, said floatation units being made from upper and lower thinwalled plastic members joined at peripheral flange portions thereof todefine a water tight compartment between said members, said flangeportions being disposed in a horizontal plane located intermediate theupper and lower extremities of said floatation units, and fastener meansextending upwardly through said flange portions into said joists tosecure said flange portions to said joists.
 2. The structure set forthin claim 1 in which one thin walled member of said floatation unit isupwardly dished from said flange and in which the other thin walledmember of said floatation unit is downwardly dished from said flange. 3.The structure set forth in claim 1 in which said floatation unit flangeportions are heat sealed together.
 4. The structure set forth in claim 1in which said joists comprise lumber of greater height than width. 5.The structure set forth in claim 1 in which one of said floatation unitmembers incorporates an upwardly formed central portion having asubstantially flat upper wall and in which the other floatation unitmembers incorporates a central downwardly formed portion having anarcuate wall.
 6. The structure set forth in claim 1 in which a lower oneof the members of said floatation units incorporates outwardlyprojecting ribs supportingly connected to said flange portions on thelower side thereof.
 7. A floatation unit for floating docks, rafts orthe like comprising a pair of formed synthetic resinous top and bottomsheets, said sheets having peripheral flanges sealed together to definea water tight compartment in the space between said sheets, said topsheet being upwardly formed in the area thereof bounded by its saidflange and being unobstructed in areas above its said flange on oppositesides thereof to permit a pair of joists or the like to be supportedthereon, said bottom sheet having load supporting ribs formed thereinand connected to its said flange to reinforce said flanges againstdownward deflection.
 8. The structure set forth in claim 7 in which saidtop sheet has a central upwardly deformed portion located entirely abovethe plane of said flange portions and in which said bottom sheet has adownwardly deformed portion located entirely beneath the plane of saidflange portions.
 9. The structure set forth in claim 8 in which said topsheet is provided with a raised generally flat top wall at the upper endthereof and in which said bottom sheet is formed with a depressedarcuate wall at the lower end thereof.
 10. The structure set forth inclaim 7 in which the flange portions of said sheets are heat sealedtogether.
 11. The structure set forth in claim 7 in which one of saidsheets is formed with inwardly depressed reinforcing ribs.
 12. Thestructure set forth in claim 7 in which said flange portions are locatedin a plane disposed above a point midway between the top of said topsheet and the bottom of said bottom sheet.
 13. The structure set forthin claim 7 in which each of said sheets is provided with a peripheralflange extending entireLy therearound and in which said flanges are heatsealed together.
 14. The structure set forth in claim 13 including loadsupporting ribs deformed outwardly from said lower sheet and mergingwith the flange of said lower sheet to provide columnar support againstdownward deflection of said lower sheet flange.